There are several hypotheses to explain the decrease in insulin sensitivity in T1D, including prolonged exposure to supraphysiological levels of exogenous insulin, genetic factors, failure to deliver insulin into the bloodstream, decreased insulin delivery to the liver, decreased hepatic IGF-1 production, abnormal regulation of glucagon, fatty acid exposure, and lipid toxicity (NEFA) [9, 48]. The gene discussed is GCG; the disease is type 1 diabetes mellitus.